connect a 12v heated bed to a 24v driven duet wifi

npm1

Hi,
I've got a silicone heated bed that has a 12v 240w sticker on it

Would connecting this to the device below allow me to connect the heater to the 24v driven duet wifi:

https://www.amazon.com/Nextrox-Converter-Regulator-Transformer-Waterproof/dp/B00BWKXTUU/ref=sr_1_1_sspa?crid=1I0DM4L4ML1IF&keywords=24v+to+12v+step+down+converter&qid=1562674788&s=gateway&sprefix=24v+to+%2Caps%2C265&sr=8-1-spons&psc=1

I wouldn't want to use another power supply to run it.

Only if you also use an external mosfet for the bed, connecting the dc/dc converter to the bed output probably wouldn't work too well, maybe if you used a low enough switching frequency.

By far the easiest method would be to run the 12v bed with 24v at a reduced duty cycle. Look at the P parameter for the M303 command. Beware this does carry some additional risk if the firmware or hardware were to have a problem leaving the heater turned on full power, but it could be mitigated by using a thermal fuse.